From 216a61d33c0728a8cf1650aaed2c523c6ce16354 Mon Sep 17 00:00:00 2001 From: Taehee Yoo Date: Fri, 4 Apr 2025 12:21:25 +0000 Subject: [PATCH] net: ethtool: fix ethtool_ringparam_get_cfg() returns a hds_thresh value always as 0. When hds-thresh is configured, ethnl_set_rings() is called, and it calls ethtool_ringparam_get_cfg() to get ringparameters from .get_ringparam() callback and dev->cfg. Both hds_config and hds_thresh values should be set from dev->cfg, not from .get_ringparam(). But ethtool_ringparam_get_cfg() sets only hds_config from dev->cfg. So, ethtool_ringparam_get_cfg() returns always a hds_thresh as 0. If an input value of hds-thresh is 0, a hds_thresh value from ethtool_ringparam_get_cfg() are same. So ethnl_set_rings() does nothing and returns immediately. It causes a bug that setting a hds-thresh value to 0 is not working. Reproducer: modprobe netdevsim echo 1 > /sys/bus/netdevsim/new_device ethtool -G eth0 hds-thresh 100 ethtool -G eth0 hds-thresh 0 ethtool -g eth0 #hds-thresh value should be 0, but it shows 100. The tools/testing/selftests/drivers/net/hds.py can test it too with applying a following patch for hds.py. Fixes: 928459bbda19 ("net: ethtool: populate the default HDS params in the core") Signed-off-by: Taehee Yoo Link: https://patch.msgid.link/20250404122126.1555648-2-ap420073@gmail.com Signed-off-by: Jakub Kicinski --- net/ethtool/common.c | 1 + 1 file changed, 1 insertion(+) diff --git a/net/ethtool/common.c b/net/ethtool/common.c index 0cb6da1f692a..49bea6b45bd5 100644 --- a/net/ethtool/common.c +++ b/net/ethtool/common.c @@ -830,6 +830,7 @@ void ethtool_ringparam_get_cfg(struct net_device *dev, /* Driver gives us current state, we want to return current config */ kparam->tcp_data_split = dev->cfg->hds_config; + kparam->hds_thresh = dev->cfg->hds_thresh; } static void ethtool_init_tsinfo(struct kernel_ethtool_ts_info *info) -- 2.49.0